Method and apparatus for making concrete pipe



Aug. 29, 1944. G. w. HurcHlNsN METHOD AND APPARATUS FOR MAKING CONCRETE PIPE Filed Jan. 28. 1942 6 sheets-sheet 1 Aug. 29, 1944# G. w. HUTCHINSON 2,356,852 METHOD AND APPARATUS Foa MAKING CONCRETE PIPE Filed Jan. 28, 1942 6 Sheets-Sheet 2 Aug 2.9, 1944- G. w. HUTcHlNsoN .l 2,356,852

METHOD AND APPARATUS FOR MAKING CONCRETE PIPE Filed Jan. 28, 1942 6 Sheets-Shee 3 'a -d un SVI/Um:

Aug 29, 1944- f G. w. HurcHlNsoN 2,356,852

METHOD AND APPARATUS FOR MAKING CONCRETE `PIPE Filed Jan. 28, 1942 6 Sheets-Sheeb 4 lily- Aug. 29, 1944. 2,356,852

METHOD AND APPARATUS FOR -MAKING CQNCRETE PIPE G. w6 HuTHlNsoN 6 Sheets-Sheet 5 'Filed Jan. 28. 1942 MTWR lg 29, 1944- G. w. Hu'rHlNsoN 2,356,852

METHOD AND APPARATUS FOR MAKING CONCRETE PIPE Filed Jan. 28, 1942 6 Sheets-Sheet 6 .13@ lv l? la? i', I126 Y 141 @l I 127 141 l l 139 I Patented Aug. 29, 1944 UNITED STATES PATENT OFFICE l METHOD AND APPARATUS Foa MAKING CONCRETE PIPE George W. Hutchinson, Raleigh, N. C. Application January 28, 1942, Serial No. 428,616

8 Claims.

This invention relates to method and apparatus for making concrete pipe. A main object of thev invention is to enable pipe of this type to be made of superior character, quickly, and with a minimum amount of equipment. To

vthese ends, a principal feature of the invention is the employment of special means for the quick and thorough compacting of the mix. Illustrative apparatus for carrying out the purposes of the invention is shown in the accompanying drawings with reference to which the description will proceed.

In the drawings:

Figure 1 is a vertical section of apparatus according to the invention, including inner and outer forms disposed in upright position for charging;

Figure 2 is a section substantially on line 2-2 of Figure 1 and shows additionally a manner in which a single line of reinforcing coil may be disposed between theforms;

Figure 3 is a section substantially on line 3-3 of Figure 1;

Figure 4 is a vertical section of apparatus in accordance with the invention utilizing a packer head to form the inside surface of the pipe;

Figure 5 is a vertical section of aV modif-led form of apparatus in accordance with the invention showing inner and outer forms in a horizontal charging position;

Figure 6 is a section substantially on line 6--6 of Figure 5;

Figure 7 is a vertical section of a still different embodiment of the invention with inner and outer forms, as in -Figures 5 and 6, in horizontal charging position;

Figure 8 is a section substantially onlin 8--8 of Figure 7;

Figure 9 is a front elevation of apparatus including the forms of Figures 7 and 8 together with handling means therefor;

Figure l0 is a side elevation of the 'apparatus of Figure 9 with the parts in different relation;

`Figure 11 is a transverse section similar in general to that of Figure 6, but showing'additionally the application of suction jacketing to the outer formi Figure 12 is a horizontal section of multiple conduit equipment according to the invention; Figure 13 is a transverse section of equipment utilizing vibrating means traversable axially of the core;

Figure 14 is a fragmentary axial section of the apparatus of Figure 13;

Figure 15 is an elevation of a detail, partly in section;

Figure 16 is a transverse section showing core vibrating means utilizing multiple vibrating units, and l Figure 17 is a partial sectional'view showing a mold detan.

Referring rst to Figures l to 3, reference numeral I5 designates a turntable mounted on rollers as at I6 and retained against horizontal displacement by a fixed ring I1. The underside ofthe turntable has fixed thereto a bevel gear I8 engaged by a bevel pinion I9 adapted to be driven through a gear 20 or the like from any suitable source of power.

Reference numeral 2l designates a cylindrical outer form which rests on the turntable and is centered thereon by a ring 22 fixed to the latter. The form 2I is diametrically split and its parts are adapted to be releasably held together by diametrically opposite sets of clamps as at 23 and 24, Figures 2 andl 3.

Concentrically disposed within the form 2| is a core 25 which includes a cylindrical shell 26, the shell having mounted on radial axes at its lower inner end rollers as at 21 by which the core is supported on the turntable. A number of generally triangular Webs 28 are welded in radial relation to the inner surface of the shell 26 and to aco-axial shaft 29 which at its lower end is provided with a socket engagedrby a centering pin 30 on the turntable.` Also flxedly secured to the adjacent inner portions of the webs, and surrounding shaft 29, is a vibrator 3I which may be of any usual construction such as now on the market and used for heavy vibrating work. Also, the inner edges of the webs 28 have welded thereto reinforcing rings 32 and 33 so that an extremely rigid core structure is provided. If desired, the webs may be provided with cutouts as shown.

Strung on shaft 29 is a spider 34 whose arnk have depending portions 35 which engage ov the outer upper end of the outer form so asfftb center the latter with respect to the shaft3f2f9 and the core. Above spider 34, shaft 29 is to a horizontal bar 36 Whose outer ends have vertical 'openings slidably receiving xedvftical columns 31 and38. The upper extti-iifity of shaft 29 is formed with an eye 39 adated to ybe hooked into by hoisting apparatus. 353m@ At its lower inner end the outer forlis welded thereto a split ring 49 which undilis the outer margins of a ring 4I which iils pthe space between the outerform and the D'Lfl'xal.

ring having a foot portion 42 of the same height as ring 4D, or of somewhat greater height.

In the use of the apparatus, the turntable is rotated at a suitable speed and carries with it the outer form, plate 4| and spider 35, which latter is freely rotatable about shaft 29. The core 25, however, is held against rotation due to its rigid connection with the cross bar 36. A stiff concrete mix is fed from a. supply hopper 43 through a spout 44 to the space between the cure and the outer form, the spider arms being preferably bevelled on top in order that the mix may readily slide therefrom. As the mix is being fed. the vibrator 3| is operated and imparts a rapid and powerful vibratory action to the shell 26 so that the mix is quickly and thoroughly compacted as it drops into the mold space, being carried around with the outer form and bottom closure ring so that the delivery from the spout is evenly distributed. The inner form exerts a troweling action'as well as imparting vibration.

While the mix is stiff, preferably with ,zero slump or better, some water will rise as the result of the'vibration and this can be drained off through small openings 45 in the outer form and the shell 26 can be similarly perforated if desired. Or, the mix may be made still drier as the top of the form is approached, coming to proper consistency by taking up the water rising from the mix at the bottom.

'I'he numerous webs 28 serve to transmit the vibrations substantially uniformly in radial directionsto the shell 26 from the vibrator 3|. It will be noted that the vibrator is disposed adjacent the top of the core and this is for the reason that since the first fed mix will be subjected to greater vibration in point of time, the strongest vibratory action should be delivered adjacent the top of the core. The disclosed arrangement gives a longitudinally balanced acti on whereby uniform denseness throughout the length of the pipe is,

secured at the time the casting operation is completed. I prefer to usevvibrators having as high frequency as possible. Vibrators at present on the market have from 3600 to 15,000 frequencies per minute, but the invention is not confined to thisrange.

As soon as the mold cavity is filled. a hoisting chain is hooked into the eye 39 and the core, together with the spider 34, is elevated above the outer form and the formed pipe within the latter. During the elevation of the core, vibration is continued for the purpose of facilitating its removal and rotation of the outer form, and therewith the formed pipe, is continued so that the core is exerting a troweling 'action on the .inner face of the pipe during its removal.

After the core has been completely removed, the turntable is stopped and the outer form, together with the formed pipe. is lifted clear and taken to storage with the pipe held in the form on bottom ring 4|. When the outer form and the pipe have been deposited, the clamps 23 and 24 are unfastened and the form is removed, leaving the pipe standing on the ring 4| as supported by the foot 42. The form may be immediately returned and reused.

If desired,. a coiled reinforcing rod can be placed in the space between the outer form and core and desirably the coil may be of the elliptical section, or plan, as shown at 46 in Figure 2 so that the coil .portions at the ends of the major axes are nearer the outer fonn than are the intermediate coil portions. Superior reinforcement is thus secured, the pipe being 4laid with the major axis of the coil upright. Whatever the shape in plan of the reinforcing coil, it can be accurately positioned between the forms by means of spacers such as shown at 46', Figure 2. These spacers, as here shown, comprise short lengths of stiff wire wrapped about and welded to the convolutions at spaced points and extending generally radially between the forms so that the coil is rigidly maintained in proper positibn during the casting of the pipe. The same spacing means may, of course, be applied to other forms of reinforce, such as wire mesh.

The apparatus asdescribed produces a cylindrical pipe of uniform wall thickness and with square ends. It will be evident, however, that various shapes of pipe with various end configurations may be formed. For example, 'a tapering section can be formed by making the core and outer form conical with small end down. The pipe can be made o f varied cross sectional contours by appropriately shaping the core and outer form. For example, these can be elliptical and in that lcase both would turn together, cross bar 36 being discarded, or both could be stationary, the mix in the latter case being fed around the cavity for evenness of distribution. To produce tongue and groove ends, for example, appropriate forms can be mounted on the bottom plate 4| and beneath the arms of spider 34 at the top of the cavity.

Bell and spigot ends can be readily produced by appropriately configuring the core and outer form to produce the bell at the upper end of the pipe.

In any event, by applying the vibration through the core, a pipe is produced vwhich is distinguishable by having an inner face thickness of greater denseness, this for the reason that the vibrations diminish in force outwardly. This is, of course, a very desirable feature since it is the inner surface of the pipe which is subject to wear in use.

In Figure 4, the outer form 41 is the same as before, but rests within a centering ring 48 on a supporting ring 49 which rims a pit 50. Reference numeral 5| designates a conventional packer head equipped with a vibrator 52 and as here shown, provided with a depending cylindrical skirt 53. Reference numeral 54 designates a bottom clos-ure ring` overlying a split abutment ring 55 fixed to the lower inner end of the outer form, ring 54 being provided with an annular` foot 56. A post 51 is fixed to the packer head in the usual manner and is rotatable by mechanism 58 and can be elevated by mechanism including the chain 59.

At the start of the forming operation, the top of the head is level with the top of ring 54 and as the mix is charged, the head is rotated and elevated and the vibrator is operated. The elevation, rotation and vibration of the packerhead is continued until the skirt is clear of the upper end of the outer form whereupon the latter, with the formed pipe therein, may be taken away as before.

The skirt 53 may be omitted, but is ordinarily provided in a length such as to extend below the zone of violent Avibration so as to prevent any tendency to cave in at this point.

Referring now to Figures 5 and 6, reference numeral 60 designates a two-part outer form annular flanges engaging around the ends of the form, the caps being secured tothe latter by hook means or clamps as at 66. Reference numeral 61 designates generally a core including a cylindrical shell 68. A shai't- 69 is supported centrally of shell 68 by rigid radial members as at 'and projects at one end. through a central opening of cap 64 and at the other end into a central opening of cap 65 so as to center the ,core. Reference numerals 1| and 12 designate vibrators which are in rigid connection with the shell 68 through a distributing system of web members as illustrated. Reference numeral 13 designates an open bottom hopper adapted to be removably supported on the outer form in register with the charging slot 63.

In the use of this apparatus, the mix is fed into the hopper and thence into the cavity between the forms, the vibrators being operated and acting to quickly compact the mix. `When the cavity has been filled, the hopper is removed and the concrete is troweled off at the slot 63. An eye 14 on the projecting end of shaft 69 can now be hooked into by a hoisting chain and the forms and the pipe confined thereby can be lifted away from the supports 6| and 62 and upended. Cap 64 is now released from the outer form and the core together with cap 64 is further elevated, with continued vibration to clear it from the formed pipe. Thereafter, the outer form, cap 65 and the formed pipe are taken away to storage and set in upright position. Upon slightly lifting the outer form, it can be unclamped and returned for reuse, the pipe remaining standing on the cap 65. v

In Figures 7 to 10, reference numeral 15 represents a dlametrically split outer form Whose sections are releasably clamped. together as before, the form being provided with a top charging slot 16. Centrally the form is equipped with horizontal trunnions 11 and 18 adapted to be supported in upwardly open notches or bearings in posts 19 and 80, Figure 9.l An end ring8l is removably secured to the outer form by means such as latches 82 pivoted on the outer form and engaging radial lugs on the ring. The ring centers one end of a core 83 whose other end is centered by an end ring or pallet 84 which lies just inwardly of abutment lugs 85 xed inside the extremity of the outer form. Ring 84 is provided with feet 86 which project beyond the end ofthe core when f the pallet is against the lugs 85.` The core 83 includes a cylindrical shell 81 and is positioned against axial displacement relative to the outer form by means of a pivoted dog 88 on ring 8| engaged in a slot of shell 81. Inwardly, the shell has secured thereto the ends of radial spider arms 89 which extend from bearing portions in which is rotatable, coaxially with the shell, a shaft 90 which is provided with eccentric weights 9|, the bearing portions being rigidly connected with the shell by a truss structure as shown. Shaft 90 is adapted to be driven rapidly from a motor 92 through a flexible shaft 93. Reference numeral 94 designates a vibrator secured centrally to the top inner side of the shell 81 and reference numeral 95 designates a vibrator secured centrally of the bottom of the outer form 15. In charging position, the described assembly is supported horizontally by posts 19 and 80 and is blocked in this position by any suitable means. A hopper 96, Figure 8, is like hopper 13 of Figures 5 and 6 except that it has a bottom closure slide 91. With the slide closed, the hopper may be lled with the mix while the forms are being put together and arranged on the supporting posts, and then may be hoisted into register with the charging slide 16 and the slide withdrawn to permit the mix to ow into the mold space. During charging the vibrators 94 and 95 are operated. When charging is completed, the hopper is removed as before and the concrete troweled olf at the slot 16.

. Reference numeral 98 designates generally a wheeled frame including across beam 99 having bottom anges on which travels a trolley I 00 of a chain hoist 0| which includes a bottom block |02 to which is swiveled a bar |03 from whose ends depend chains |04 and |05 provided with hooks at their free ends. After the pipe has been formed in the manner abov'e described, the molding apparatus is unblocked and swung tmthe upright position shown in Figure 9. Chains |04 and |05 are now hooked into loops |06 and |01 on the outer form and the apparatus is lifted away from the posts and set on the iioor in upright position. Dog 88 is now released and the chains |04' and |05 are engaged with arms of the upper spider 89 and the core is lifted up'and away while Vibration is applied by operating eccentically weighted shaft 90, the other vibrators being inactive at this time. Rotation of shaft exerts a rotary effect on the core 83 and consequently, if the outer form is held, there will be a troweling action on the inner surface of the pipe as the core is Withdrawn.

It will be obvious that the forms 15 and 81 can be of any desired cross sectional conilguration, and that any desired end coniiguration can be applied to the pipe. As shown in Figure '7, for example, the end rings 8| and 84 are provided with annular formations |08 and |09 for the produc tion of tongue and groove ends.

Obviously, a core like that of Figures 5 and 6 could be substituted in the assembly shown in Figures 7 and 8.

In Figure 11, the core I0 is assumed to be the same as that shown in Figures 5 and 6. The outer form is provided with a top charging slot and is split top and bottom and'its sections hinged together at the bottom, being retained in closed rela-tion by cap members such as shown in'Figure 5 and also by auxiliary clamp means so as to prevent opening when the core is being removed. The outer form is provided with a multiplicity of small openings and with jackets ||2 and ||'3 which lead to a source of suction through hoses as at I4. Trunnions ||5 and 6 are provided for the support of the forms in the mannerdescribed in connection with Figures l'7 to 10. In the use of this apparatus, vibration is applied during the charging operation and suction is also applied so that' any excess water is withdrawn, thus rendering the pipe all the more stable. Suction can be continued for any desired length of time after charging has been completed.

In Figure 12 reference numeral |20 designates an outer form which is square in section and composed of two parts releasably securedtogether by clamps along diagonally opposite edges. As before, a bottom plate or pallet overlies inner bot-I tom lugs on the outer form and has foot portions in the nature of those shown at 86 in Figure 7. The pallet, as here contemplated, has four symmetrically arranged bottom openings which receive, and position the lower ends of shafts |2| of cores |22 which are. equipped with vibrators |23 and distributing webs I 24 like those inFigures 1 and 3. With the cores disposed as shown, the concrete mix is charged into the outer form while the inner cores are" vibrating and when the casting is completed the cores are withdrawn singlyor simultaneously while still being vibrated. In this manner a conduit section having four passages is produced. Obviously, the external contour of the conduit can be determined as desired by the use of appropriate outer forms and the number and arrangement of openings can be determined by the use of an appropriately disposed number of cores.

According to Figures 13 and 14, the outer form |50 rests on a flanged ring |5| which rims a pit |52 and the inturned lower edge of the form supports a pallet |53 which centers the lower end of the inner form |25. `An appropriate end plate orbpallet is provided at the upper end of the forms and the inner form is supported by any suitable means either from above or from below. Both of the forms are provided throughout with small perforations |215 and |50 for the escape of excess water from the mix. These slots may have a width of 1*.;- inch, for example. In this case the inner form is shown as being split on one side at |54 and extending along the inner margins of the form at each side of the split are angles |55 and |56 with whichis engaged a longitudinally extending locking plate |51 which serves to hold the adjacent edges of the core in register. By removing the plate one edge can be sprung over the other so as to slightly collapse the core to facilitate its removal.

Reference numeral |26 designates a vibrator body slidable on an axial shaft |21 whose lower end is supported by an arm |21 projecting radially inwardly from the wall of core |25, the upper end of the shaft being similarly or otherwise appropriately centered. Projecting from the body |26 are a number of radiating arms |28 having rollers |29 at their outer ends bearing against the inner walls of the core. At the beginning of the charging operation the vibrator assembly is at the bottom of the inner core and as charging continues it is elevated by means such as a chain |30, following the level of the mix upwardly. In this manner the maximum effect of the vibrator is transmitted to the core throughout the length of the latter and the cornpacting of the concrete be progressively completed upwardly with resulting uniformity throughout. Obviously the vibrator assembly may be held stationary in a position to give a predominant upper effect as in Figure 1. On the completion of the casting operation the core is permitted to drop under its own weight into the pit |52. This can be facilitated by removing plate |51 and springing one edge of the core, at the split |54, slightly over the other to contract the core. This can be done to some extent without removal of the vibrator assembly, or the latter may be removed if desired. In any event, after the core has been dropped below the pallet |53, the outer form, carrying the pipe, can be lifted away and upon deposit the outer form can be removed, leaving the pipe supported on the pallet for curing.

In Figure the arm |20' is shown as being composed of telescoped portions |3| and |32,

.the -latter having a pin |33 working in a longitudinal slot |34 of the former. A nut |35 is swiveled on portion |3| and threaded on portion |32. By adjusting the nut substantially uniform contact of all of the rollers |35 against the inner surface of the core, |25 can be obtained.

Figure 16 shows a traversable vibrator assembly including three vibrators |31, |38 and |39 equi-angularly disposed about a central ring |40 which is slidable on shaft |21, the vibrators being joined to the ring by arms as shown, and to an outer framework carrying rollers |4|. In this arrangement the several vibrators exert a combined powerful action which is the more effective in view of the closeness of the vibrators to the inner walls of the core |25. During casting the vibrator assembly is elevated as in the embodiment of Figures 13 and 14.

Machine made pipe sections of ordinary length produced in accordance with the invention will stand without any danger of collapse upon immediate removal of both the inner and outer forms and the same applies to longer lengths which, under previous practices, would collapse upon the removal of peripheral support. In any event, in the case of such longer lengths, the quality of concrete produced will be such as to permit earlier removal of'the forms than heretofore possible. Whenthe pipe is cast in horizontal position it is preferably up-ended, as described, while removing the core. However, with an originally stiftmix, thoroughly treated by vibration in accordance with the invention, the core may be immediately removed horizontally without collapsing the pipe.

In the case of large diameter pipe, the wall thickness may in some cases be too great to enable the vibration of the core, unless the vibratory effect is increased, tov carry through sufficiently powerfully to the outer form and in this cas'e a wetter mix would be necessary. In vertical casting apparatus such for example as is shown in Figure 1, this wetter mix can, of course, be readily handled, the only difference from the described procedure being that the forms cannot be immediately removed at the completion of casting. In the case of horizontal casting with apparatus such as is shown in Figures 7 and 8, the outer form 15, Figure 1'7, may have hinged thereto along one margin of slot 1S, asv at |40, a door or closure |4| which can be swung to the closed position shown and secured by latches as at |42 so that upon up-ending the assembly there will be no danger of the loss 'of concrete through the slot. As shown in Figure I1, the closure has a downward longitudinal offset |43 which is transversely curved on the arc of the outer form so that when the door is closed the inner surface of the outer form is substantially continuous throughout. During charging the door may be swung back out of the way so that the charging hopper may be positioned above the slot as in Figure 8.

It Will be understood that in horizontal casting the same spacer means for the reinforce as shown in Figure 2. may be used. The spacer members, rigidly secured to the reinforce and extending freely therefrom in both directions, engage the inner and outer forms so that the reinforce will be retained in its designated position during lcasting. It may be pointed out that in horizontal casting a superior bond between the concrete and the circumferentially disposed reinforce is secured as compared with the result in vertical casting. In vertical casting the water which rises from the concrete forms a lm on the bottom portions of the horizontal, or nearly horizontal, portions of the reinforce so that anl formiy bonded to the steel substantially throughout.

- and this is particularly so when a relatively wet mix is being used.

While I have shown varied apparatus for carrying out the new method, it Will be understood that I do not necessarily limit myself to the use of any specific. disclosure herein, the scope of the invention being dened in the following claims.

I claim:

1. The method of making concrete pipe which comprises feeding a stii concrete mix into the space between a cylindrical core and an outer form, imparting rapid axially and circumferentially distributed vibrations to the core from -within the latter during feed whereby to compact the mix, relatively rotating the'core and the formed pipe, and moving the core and formed pipe axially apart while continuing the relative rotation and vibrating the core to facilitate its release from the pipe.

2. The method of making concrete pipe which comprises feeding a stiff concrete mix into the space between a core and an outer form which are horizontally disposed, imparting rapid axially and circumferentially distributed vibrations to the core from within the latter during feed whereby to compact the mix, up-ending the core and form with the formed pipe therebetween, and moving the core and form axially apart while vibrating the core to facilitate its release from the pipe.

3. Apparatus for making concrete pipe, comprising a core and an outer form dening between them a space for the reception of the mix, vibrating means within the core, and vibration transmitting truss systems connecting the vibrating means with the core at circumferentially and axially distributed areas of the latter.

4. Apparatus for making concrete pipe, comprising a core and an outer form, means for maintaining the core within the form in peripherally spaced relation thereto comprising closure means for the ends of the space between said core and form, means for releasably holding said closure means in operative position, trunnions on said form, and supporting means providing bearings for said trunnions whereby the form and therewith the core may be supported in horizontal or uprightl position, said form having a charging opening which is on top when the form is in horizontal position.

5. Apparatus for making concrete pipe comprising an outer form, a packer head, and a vibrating unit carried by said head.

6. Apparatus for making concrete pipe comprising an outer form, an inner form, and a vibrating unit comprising a vibrator and vibration transmitting means adapted to be traversed axially of the inner form with said transmitting means in contact with the inner surfaces of the latter.

7. Apparatus for making concrete pipe, comprising acore and an outer form dening be- A tween them a space for the reception of the mix, a vibrating means disposed within the core, and a vibration distributing system of rigid truss members between the vibrating means and core;

8. Apparatus for making concrete'pipe, `comprising an outer form and a cylindrical compacting and forming unit within said form and peripherally spaced therefrom, vibrating means carried by said unit for imparting rapid vibration thereto to compact the mix introduced into the space between said form and unit, means for elevating said unit relative to the form, and means for relatively rotating said form and unit While the latter is being `elevated and vibrated.

GEORGE W. HUTCHINSON. 

